Downstream insertion of the adenovirus tripartite leader sequence enhances expression in universal eukaryotic vectors

A series of universal eukaryotic gene expression vectors was constructed. All vectors contain a viral promoter and enhancer, a polylinker for insertion of the gene of interest and a polyadenylation sequence. To enhance translation, we inserted the tripartite leader sequence of an adenovirus downstream of the promoter. Using the chloramphenicol acetyl transferase (cat) gene as a marker, we show that the strength of various promoters/enhancers in different cell lines differed by two orders of magnitude. The presence of the tripartite leader increased the efficiency of gene expression up to 18-fold. The level of increase is promoter specific and is most likely influenced by additional sequences flanking the tripartite leader sequence.